﻿/*
 * FCKeditor - The text editor for Internet - http://www.fckeditor.net
 * Copyright (C) 2003-2009 Frederico Caldeira Knabben
 *
 * == BEGIN LICENSE ==
 *
 * Licensed under the terms of any of the following licenses at your
 * choice:
 *
 *  - GNU General Public License Version 2 or later (the "GPL")
 *    http://www.gnu.org/licenses/gpl.html
 *
 *  - GNU Lesser General Public License Version 2.1 or later (the "LGPL")
 *    http://www.gnu.org/licenses/lgpl.html
 *
 *  - Mozilla Public License Version 1.1 or later (the "MPL")
 *    http://www.mozilla.org/MPL/MPL-1.1.html
 *
 * == END LICENSE ==
 *
 * Control keyboard keystroke combinations.
 */

var FCKKeystrokeHandler = function( cancelCtrlDefaults )
{
    this.Keystrokes = new Object() ;
    this.CancelCtrlDefaults = ( cancelCtrlDefaults !== false ) ;
}

/*
 * Listen to keystroke events in an element or DOM document object.
 *        @target: The element or document to listen to keystroke events.
 */
FCKKeystrokeHandler.prototype.AttachToElement = function( target )
{
    // For newer browsers, it is enough to listen to the keydown event only.
    // Some browsers instead, don't cancel key events in the keydown, but in the
    // keypress. So we must do a longer trip in those cases.
    FCKTools.AddEventListenerEx( target, 'keydown', _FCKKeystrokeHandler_OnKeyDown, this ) ;
    if ( FCKBrowserInfo.IsGecko10 || FCKBrowserInfo.IsOpera || ( FCKBrowserInfo.IsGecko && FCKBrowserInfo.IsMac ) )
        FCKTools.AddEventListenerEx( target, 'keypress', _FCKKeystrokeHandler_OnKeyPress, this ) ;
}

/*
 * Sets a list of keystrokes. It can receive either a single array or "n"
 * arguments, each one being an array of 1 or 2 elemenst. The first element
 * is the keystroke combination, and the second is the value to assign to it.
 * If the second element is missing, the keystroke definition is removed.
 */
FCKKeystrokeHandler.prototype.SetKeystrokes = function()
{
    // Look through the arguments.
    for ( var i = 0 ; i < arguments.length ; i++ )
    {
        var keyDef = arguments[i] ;

        // If the configuration for the keystrokes is missing some element or has any extra comma
        // this item won't be valid, so skip it and keep on processing.
        if ( !keyDef )
            continue ;

        if ( typeof( keyDef[0] ) == 'object' )        // It is an array with arrays defining the keystrokes.
            this.SetKeystrokes.apply( this, keyDef ) ;
        else
        {
            if ( keyDef.length == 1 )        // If it has only one element, remove the keystroke.
                delete this.Keystrokes[ keyDef[0] ] ;
            else                            // Otherwise add it.
                this.Keystrokes[ keyDef[0] ] = keyDef[1] === true ? true : keyDef ;
        }
    }
}

function _FCKKeystrokeHandler_OnKeyDown( ev, keystrokeHandler )
{
    // Get the key code.
    var keystroke = ev.keyCode || ev.which ;

    // Combine it with the CTRL, SHIFT and ALT states.
    var keyModifiers = 0 ;

    if ( ev.ctrlKey || ev.metaKey )
        keyModifiers += CTRL ;

    if ( ev.shiftKey )
        keyModifiers += SHIFT ;

    if ( ev.altKey )
        keyModifiers += ALT ;

    var keyCombination = keystroke + keyModifiers ;

    var cancelIt = keystrokeHandler._CancelIt = false ;

    // Look for its definition availability.
    var keystrokeValue = keystrokeHandler.Keystrokes[ keyCombination ] ;

//    FCKDebug.Output( 'KeyDown: ' + keyCombination + ' - Value: ' + keystrokeValue ) ;

    // If the keystroke is defined
    if ( keystrokeValue )
    {
        // If the keystroke has been explicitly set to "true" OR calling the
        // "OnKeystroke" event, it doesn't return "true", the default behavior
        // must be preserved.
        if ( keystrokeValue === true || !( keystrokeHandler.OnKeystroke && keystrokeHandler.OnKeystroke.apply( keystrokeHandler, keystrokeValue ) ) )
            return true ;

        cancelIt = true ;
    }

    // By default, it will cancel all combinations with the CTRL key only (except positioning keys).
    if ( cancelIt || ( keystrokeHandler.CancelCtrlDefaults && keyModifiers == CTRL && ( keystroke < 33 || keystroke > 40 ) ) )
    {
        keystrokeHandler._CancelIt = true ;

        if ( ev.preventDefault )
            return ev.preventDefault() ;

        ev.returnValue = false ;
        ev.cancelBubble = true ;
        return false ;
    }

    return true ;
}

function _FCKKeystrokeHandler_OnKeyPress( ev, keystrokeHandler )
{
    if ( keystrokeHandler._CancelIt )
    {
//        FCKDebug.Output( 'KeyPress Cancel', 'Red') ;

        if ( ev.preventDefault )
            return ev.preventDefault() ;

        return false ;
    }

    return true ;
}
